1 /* $NetBSD: vfs_mount.c,v 1.70 2019/02/20 10:08:37 hannken Exp $ */ 2 3 /*- 4 * Copyright (c) 1997-2011 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center, by Charles M. Hannum, and by Andrew Doran. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 30 * POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 /* 34 * Copyright (c) 1989, 1993 35 * The Regents of the University of California. All rights reserved. 36 * (c) UNIX System Laboratories, Inc. 37 * All or some portions of this file are derived from material licensed 38 * to the University of California by American Telephone and Telegraph 39 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 40 * the permission of UNIX System Laboratories, Inc. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 3. Neither the name of the University nor the names of its contributors 51 * may be used to endorse or promote products derived from this software 52 * without specific prior written permission. 53 * 54 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 55 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 56 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 57 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 58 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 59 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 60 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 61 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 62 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 63 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 64 * SUCH DAMAGE. 65 * 66 * @(#)vfs_subr.c 8.13 (Berkeley) 4/18/94 67 */ 68 69 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: vfs_mount.c,v 1.70 2019/02/20 10:08:37 hannken Exp $"); 71 72 #include <sys/param.h> 73 #include <sys/kernel.h> 74 75 #include <sys/atomic.h> 76 #include <sys/buf.h> 77 #include <sys/conf.h> 78 #include <sys/fcntl.h> 79 #include <sys/filedesc.h> 80 #include <sys/device.h> 81 #include <sys/kauth.h> 82 #include <sys/kmem.h> 83 #include <sys/module.h> 84 #include <sys/mount.h> 85 #include <sys/fstrans.h> 86 #include <sys/namei.h> 87 #include <sys/extattr.h> 88 #include <sys/syscallargs.h> 89 #include <sys/sysctl.h> 90 #include <sys/systm.h> 91 #include <sys/vfs_syscalls.h> 92 #include <sys/vnode_impl.h> 93 94 #include <miscfs/genfs/genfs.h> 95 #include <miscfs/specfs/specdev.h> 96 97 enum mountlist_type { 98 ME_MOUNT, 99 ME_MARKER 100 }; 101 struct mountlist_entry { 102 TAILQ_ENTRY(mountlist_entry) me_list; /* Mount list. */ 103 struct mount *me_mount; /* Actual mount if ME_MOUNT, 104 current mount else. */ 105 enum mountlist_type me_type; /* Mount or marker. */ 106 }; 107 struct mount_iterator { 108 struct mountlist_entry mi_entry; 109 }; 110 111 static struct vnode *vfs_vnode_iterator_next1(struct vnode_iterator *, 112 bool (*)(void *, struct vnode *), void *, bool); 113 114 /* Root filesystem. */ 115 vnode_t * rootvnode; 116 117 /* Mounted filesystem list. */ 118 static TAILQ_HEAD(mountlist, mountlist_entry) mountlist; 119 static kmutex_t mountlist_lock; 120 int vnode_offset_next_by_lru /* XXX: ugly hack for pstat.c */ 121 = offsetof(vnode_impl_t, vi_lrulist.tqe_next); 122 123 kmutex_t mntvnode_lock; 124 kmutex_t vfs_list_lock; 125 126 static specificdata_domain_t mount_specificdata_domain; 127 static kmutex_t mntid_lock; 128 129 static kmutex_t mountgen_lock; 130 static uint64_t mountgen; 131 132 void 133 vfs_mount_sysinit(void) 134 { 135 136 TAILQ_INIT(&mountlist); 137 mutex_init(&mountlist_lock, MUTEX_DEFAULT, IPL_NONE); 138 mutex_init(&mntvnode_lock, MUTEX_DEFAULT, IPL_NONE); 139 mutex_init(&vfs_list_lock, MUTEX_DEFAULT, IPL_NONE); 140 141 mount_specificdata_domain = specificdata_domain_create(); 142 mutex_init(&mntid_lock, MUTEX_DEFAULT, IPL_NONE); 143 mutex_init(&mountgen_lock, MUTEX_DEFAULT, IPL_NONE); 144 mountgen = 0; 145 } 146 147 struct mount * 148 vfs_mountalloc(struct vfsops *vfsops, vnode_t *vp) 149 { 150 struct mount *mp; 151 int error __diagused; 152 153 mp = kmem_zalloc(sizeof(*mp), KM_SLEEP); 154 mp->mnt_op = vfsops; 155 mp->mnt_refcnt = 1; 156 TAILQ_INIT(&mp->mnt_vnodelist); 157 mutex_init(&mp->mnt_renamelock, MUTEX_DEFAULT, IPL_NONE); 158 mutex_init(&mp->mnt_updating, MUTEX_DEFAULT, IPL_NONE); 159 mp->mnt_vnodecovered = vp; 160 mount_initspecific(mp); 161 162 error = fstrans_mount(mp); 163 KASSERT(error == 0); 164 165 mutex_enter(&mountgen_lock); 166 mp->mnt_gen = mountgen++; 167 mutex_exit(&mountgen_lock); 168 169 return mp; 170 } 171 172 /* 173 * vfs_rootmountalloc: lookup a filesystem type, and if found allocate and 174 * initialize a mount structure for it. 175 * 176 * Devname is usually updated by mount(8) after booting. 177 */ 178 int 179 vfs_rootmountalloc(const char *fstypename, const char *devname, 180 struct mount **mpp) 181 { 182 struct vfsops *vfsp = NULL; 183 struct mount *mp; 184 int error __diagused; 185 186 mutex_enter(&vfs_list_lock); 187 LIST_FOREACH(vfsp, &vfs_list, vfs_list) 188 if (!strncmp(vfsp->vfs_name, fstypename, 189 sizeof(mp->mnt_stat.f_fstypename))) 190 break; 191 if (vfsp == NULL) { 192 mutex_exit(&vfs_list_lock); 193 return (ENODEV); 194 } 195 vfsp->vfs_refcount++; 196 mutex_exit(&vfs_list_lock); 197 198 if ((mp = vfs_mountalloc(vfsp, NULL)) == NULL) 199 return ENOMEM; 200 error = vfs_busy(mp); 201 KASSERT(error == 0); 202 mp->mnt_flag = MNT_RDONLY; 203 (void)strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfs_name, 204 sizeof(mp->mnt_stat.f_fstypename)); 205 mp->mnt_stat.f_mntonname[0] = '/'; 206 mp->mnt_stat.f_mntonname[1] = '\0'; 207 mp->mnt_stat.f_mntfromname[sizeof(mp->mnt_stat.f_mntfromname) - 1] = 208 '\0'; 209 (void)copystr(devname, mp->mnt_stat.f_mntfromname, 210 sizeof(mp->mnt_stat.f_mntfromname) - 1, 0); 211 *mpp = mp; 212 return 0; 213 } 214 215 /* 216 * vfs_getnewfsid: get a new unique fsid. 217 */ 218 void 219 vfs_getnewfsid(struct mount *mp) 220 { 221 static u_short xxxfs_mntid; 222 fsid_t tfsid; 223 int mtype; 224 225 mutex_enter(&mntid_lock); 226 mtype = makefstype(mp->mnt_op->vfs_name); 227 mp->mnt_stat.f_fsidx.__fsid_val[0] = makedev(mtype, 0); 228 mp->mnt_stat.f_fsidx.__fsid_val[1] = mtype; 229 mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0]; 230 if (xxxfs_mntid == 0) 231 ++xxxfs_mntid; 232 tfsid.__fsid_val[0] = makedev(mtype & 0xff, xxxfs_mntid); 233 tfsid.__fsid_val[1] = mtype; 234 while (vfs_getvfs(&tfsid)) { 235 tfsid.__fsid_val[0]++; 236 xxxfs_mntid++; 237 } 238 mp->mnt_stat.f_fsidx.__fsid_val[0] = tfsid.__fsid_val[0]; 239 mp->mnt_stat.f_fsid = mp->mnt_stat.f_fsidx.__fsid_val[0]; 240 mutex_exit(&mntid_lock); 241 } 242 243 /* 244 * Lookup a mount point by filesystem identifier. 245 * 246 * XXX Needs to add a reference to the mount point. 247 */ 248 struct mount * 249 vfs_getvfs(fsid_t *fsid) 250 { 251 mount_iterator_t *iter; 252 struct mount *mp; 253 254 mountlist_iterator_init(&iter); 255 while ((mp = mountlist_iterator_next(iter)) != NULL) { 256 if (mp->mnt_stat.f_fsidx.__fsid_val[0] == fsid->__fsid_val[0] && 257 mp->mnt_stat.f_fsidx.__fsid_val[1] == fsid->__fsid_val[1]) { 258 mountlist_iterator_destroy(iter); 259 return mp; 260 } 261 } 262 mountlist_iterator_destroy(iter); 263 return NULL; 264 } 265 266 /* 267 * Take a reference to a mount structure. 268 */ 269 void 270 vfs_ref(struct mount *mp) 271 { 272 273 KASSERT(mp->mnt_refcnt > 0 || mutex_owned(&mountlist_lock)); 274 275 atomic_inc_uint(&mp->mnt_refcnt); 276 } 277 278 /* 279 * Drop a reference to a mount structure, freeing if the last reference. 280 */ 281 void 282 vfs_rele(struct mount *mp) 283 { 284 285 if (__predict_true((int)atomic_dec_uint_nv(&mp->mnt_refcnt) > 0)) { 286 return; 287 } 288 289 /* 290 * Nothing else has visibility of the mount: we can now 291 * free the data structures. 292 */ 293 KASSERT(mp->mnt_refcnt == 0); 294 specificdata_fini(mount_specificdata_domain, &mp->mnt_specdataref); 295 mutex_destroy(&mp->mnt_updating); 296 mutex_destroy(&mp->mnt_renamelock); 297 if (mp->mnt_op != NULL) { 298 vfs_delref(mp->mnt_op); 299 } 300 fstrans_unmount(mp); 301 /* 302 * Final free of mp gets done from fstrans_mount_dtor(). 303 * 304 * Prevents this memory to be reused as a mount before 305 * fstrans releases all references to it. 306 */ 307 } 308 309 /* 310 * Mark a mount point as busy, and gain a new reference to it. Used to 311 * prevent the file system from being unmounted during critical sections. 312 * 313 * vfs_busy can be called multiple times and by multiple threads 314 * and must be accompanied by the same number of vfs_unbusy calls. 315 * 316 * => The caller must hold a pre-existing reference to the mount. 317 * => Will fail if the file system is being unmounted, or is unmounted. 318 */ 319 static inline int 320 _vfs_busy(struct mount *mp, bool wait) 321 { 322 323 KASSERT(mp->mnt_refcnt > 0); 324 325 if (wait) { 326 fstrans_start(mp); 327 } else { 328 if (fstrans_start_nowait(mp)) 329 return EBUSY; 330 } 331 if (__predict_false((mp->mnt_iflag & IMNT_GONE) != 0)) { 332 fstrans_done(mp); 333 return ENOENT; 334 } 335 vfs_ref(mp); 336 return 0; 337 } 338 339 int 340 vfs_busy(struct mount *mp) 341 { 342 343 return _vfs_busy(mp, true); 344 } 345 346 int 347 vfs_trybusy(struct mount *mp) 348 { 349 350 return _vfs_busy(mp, false); 351 } 352 353 /* 354 * Unbusy a busy filesystem. 355 * 356 * Every successful vfs_busy() call must be undone by a vfs_unbusy() call. 357 */ 358 void 359 vfs_unbusy(struct mount *mp) 360 { 361 362 KASSERT(mp->mnt_refcnt > 0); 363 364 fstrans_done(mp); 365 vfs_rele(mp); 366 } 367 368 struct vnode_iterator { 369 vnode_impl_t vi_vnode; 370 }; 371 372 void 373 vfs_vnode_iterator_init(struct mount *mp, struct vnode_iterator **vnip) 374 { 375 vnode_t *vp; 376 vnode_impl_t *vip; 377 378 vp = vnalloc_marker(mp); 379 vip = VNODE_TO_VIMPL(vp); 380 381 mutex_enter(&mntvnode_lock); 382 TAILQ_INSERT_HEAD(&mp->mnt_vnodelist, vip, vi_mntvnodes); 383 vp->v_usecount = 1; 384 mutex_exit(&mntvnode_lock); 385 386 *vnip = (struct vnode_iterator *)vip; 387 } 388 389 void 390 vfs_vnode_iterator_destroy(struct vnode_iterator *vni) 391 { 392 vnode_impl_t *mvip = &vni->vi_vnode; 393 vnode_t *mvp = VIMPL_TO_VNODE(mvip); 394 395 mutex_enter(&mntvnode_lock); 396 KASSERT(vnis_marker(mvp)); 397 if (mvp->v_usecount != 0) { 398 TAILQ_REMOVE(&mvp->v_mount->mnt_vnodelist, mvip, vi_mntvnodes); 399 mvp->v_usecount = 0; 400 } 401 mutex_exit(&mntvnode_lock); 402 vnfree_marker(mvp); 403 } 404 405 static struct vnode * 406 vfs_vnode_iterator_next1(struct vnode_iterator *vni, 407 bool (*f)(void *, struct vnode *), void *cl, bool do_wait) 408 { 409 vnode_impl_t *mvip = &vni->vi_vnode; 410 struct mount *mp = VIMPL_TO_VNODE(mvip)->v_mount; 411 vnode_t *vp; 412 vnode_impl_t *vip; 413 int error; 414 415 KASSERT(vnis_marker(VIMPL_TO_VNODE(mvip))); 416 417 do { 418 mutex_enter(&mntvnode_lock); 419 vip = TAILQ_NEXT(mvip, vi_mntvnodes); 420 TAILQ_REMOVE(&mp->mnt_vnodelist, mvip, vi_mntvnodes); 421 VIMPL_TO_VNODE(mvip)->v_usecount = 0; 422 again: 423 vp = VIMPL_TO_VNODE(vip); 424 if (vp == NULL) { 425 mutex_exit(&mntvnode_lock); 426 return NULL; 427 } 428 mutex_enter(vp->v_interlock); 429 if (vnis_marker(vp) || 430 vdead_check(vp, (do_wait ? 0 : VDEAD_NOWAIT)) || 431 (f && !(*f)(cl, vp))) { 432 mutex_exit(vp->v_interlock); 433 vip = TAILQ_NEXT(vip, vi_mntvnodes); 434 goto again; 435 } 436 437 TAILQ_INSERT_AFTER(&mp->mnt_vnodelist, vip, mvip, vi_mntvnodes); 438 VIMPL_TO_VNODE(mvip)->v_usecount = 1; 439 mutex_exit(&mntvnode_lock); 440 error = vcache_vget(vp); 441 KASSERT(error == 0 || error == ENOENT); 442 } while (error != 0); 443 444 return vp; 445 } 446 447 struct vnode * 448 vfs_vnode_iterator_next(struct vnode_iterator *vni, 449 bool (*f)(void *, struct vnode *), void *cl) 450 { 451 452 return vfs_vnode_iterator_next1(vni, f, cl, false); 453 } 454 455 /* 456 * Move a vnode from one mount queue to another. 457 */ 458 void 459 vfs_insmntque(vnode_t *vp, struct mount *mp) 460 { 461 vnode_impl_t *vip = VNODE_TO_VIMPL(vp); 462 struct mount *omp; 463 464 KASSERT(mp == NULL || (mp->mnt_iflag & IMNT_UNMOUNT) == 0 || 465 vp->v_tag == VT_VFS); 466 467 mutex_enter(&mntvnode_lock); 468 /* 469 * Delete from old mount point vnode list, if on one. 470 */ 471 if ((omp = vp->v_mount) != NULL) 472 TAILQ_REMOVE(&vp->v_mount->mnt_vnodelist, vip, vi_mntvnodes); 473 /* 474 * Insert into list of vnodes for the new mount point, if 475 * available. The caller must take a reference on the mount 476 * structure and donate to the vnode. 477 */ 478 if ((vp->v_mount = mp) != NULL) 479 TAILQ_INSERT_TAIL(&mp->mnt_vnodelist, vip, vi_mntvnodes); 480 mutex_exit(&mntvnode_lock); 481 482 if (omp != NULL) { 483 /* Release reference to old mount. */ 484 vfs_rele(omp); 485 } 486 } 487 488 /* 489 * Remove any vnodes in the vnode table belonging to mount point mp. 490 * 491 * If FORCECLOSE is not specified, there should not be any active ones, 492 * return error if any are found (nb: this is a user error, not a 493 * system error). If FORCECLOSE is specified, detach any active vnodes 494 * that are found. 495 * 496 * If WRITECLOSE is set, only flush out regular file vnodes open for 497 * writing. 498 * 499 * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped. 500 */ 501 #ifdef DEBUG 502 int busyprt = 0; /* print out busy vnodes */ 503 struct ctldebug debug1 = { "busyprt", &busyprt }; 504 #endif 505 506 static vnode_t * 507 vflushnext(struct vnode_iterator *marker, int *when) 508 { 509 if (hardclock_ticks > *when) { 510 yield(); 511 *when = hardclock_ticks + hz / 10; 512 } 513 return vfs_vnode_iterator_next1(marker, NULL, NULL, true); 514 } 515 516 /* 517 * Flush one vnode. Referenced on entry, unreferenced on return. 518 */ 519 static int 520 vflush_one(vnode_t *vp, vnode_t *skipvp, int flags) 521 { 522 int error; 523 struct vattr vattr; 524 525 if (vp == skipvp || 526 ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM))) { 527 vrele(vp); 528 return 0; 529 } 530 /* 531 * If WRITECLOSE is set, only flush out regular file 532 * vnodes open for writing or open and unlinked. 533 */ 534 if ((flags & WRITECLOSE)) { 535 if (vp->v_type != VREG) { 536 vrele(vp); 537 return 0; 538 } 539 error = vn_lock(vp, LK_EXCLUSIVE); 540 if (error) { 541 KASSERT(error == ENOENT); 542 vrele(vp); 543 return 0; 544 } 545 error = VOP_FSYNC(vp, curlwp->l_cred, FSYNC_WAIT, 0, 0); 546 if (error == 0) 547 error = VOP_GETATTR(vp, &vattr, curlwp->l_cred); 548 VOP_UNLOCK(vp); 549 if (error) { 550 vrele(vp); 551 return error; 552 } 553 if (vp->v_writecount == 0 && vattr.va_nlink > 0) { 554 vrele(vp); 555 return 0; 556 } 557 } 558 /* 559 * First try to recycle the vnode. 560 */ 561 if (vrecycle(vp)) 562 return 0; 563 /* 564 * If FORCECLOSE is set, forcibly close the vnode. 565 * For block or character devices, revert to an 566 * anonymous device. For all other files, just 567 * kill them. 568 */ 569 if (flags & FORCECLOSE) { 570 if (vp->v_usecount > 1 && 571 (vp->v_type == VBLK || vp->v_type == VCHR)) 572 vcache_make_anon(vp); 573 else 574 vgone(vp); 575 return 0; 576 } 577 vrele(vp); 578 return EBUSY; 579 } 580 581 int 582 vflush(struct mount *mp, vnode_t *skipvp, int flags) 583 { 584 vnode_t *vp; 585 struct vnode_iterator *marker; 586 int busy, error, when, retries = 2; 587 588 do { 589 busy = error = when = 0; 590 591 /* 592 * First, flush out any vnode references from the 593 * deferred vrele list. 594 */ 595 vrele_flush(mp); 596 597 vfs_vnode_iterator_init(mp, &marker); 598 599 while ((vp = vflushnext(marker, &when)) != NULL) { 600 error = vflush_one(vp, skipvp, flags); 601 if (error == EBUSY) { 602 error = 0; 603 busy++; 604 #ifdef DEBUG 605 if (busyprt && retries == 0) 606 vprint("vflush: busy vnode", vp); 607 #endif 608 } else if (error != 0) { 609 break; 610 } 611 } 612 613 vfs_vnode_iterator_destroy(marker); 614 } while (error == 0 && busy > 0 && retries-- > 0); 615 616 if (error) 617 return error; 618 if (busy) 619 return EBUSY; 620 return 0; 621 } 622 623 /* 624 * Mount a file system. 625 */ 626 627 /* 628 * Scan all active processes to see if any of them have a current or root 629 * directory onto which the new filesystem has just been mounted. If so, 630 * replace them with the new mount point. 631 */ 632 static void 633 mount_checkdirs(vnode_t *olddp) 634 { 635 vnode_t *newdp, *rele1, *rele2; 636 struct cwdinfo *cwdi; 637 struct proc *p; 638 bool retry; 639 640 if (olddp->v_usecount == 1) { 641 return; 642 } 643 if (VFS_ROOT(olddp->v_mountedhere, &newdp)) 644 panic("mount: lost mount"); 645 646 do { 647 retry = false; 648 mutex_enter(proc_lock); 649 PROCLIST_FOREACH(p, &allproc) { 650 if ((cwdi = p->p_cwdi) == NULL) 651 continue; 652 /* 653 * Cannot change to the old directory any more, 654 * so even if we see a stale value it is not a 655 * problem. 656 */ 657 if (cwdi->cwdi_cdir != olddp && 658 cwdi->cwdi_rdir != olddp) 659 continue; 660 retry = true; 661 rele1 = NULL; 662 rele2 = NULL; 663 atomic_inc_uint(&cwdi->cwdi_refcnt); 664 mutex_exit(proc_lock); 665 rw_enter(&cwdi->cwdi_lock, RW_WRITER); 666 if (cwdi->cwdi_cdir == olddp) { 667 rele1 = cwdi->cwdi_cdir; 668 vref(newdp); 669 cwdi->cwdi_cdir = newdp; 670 } 671 if (cwdi->cwdi_rdir == olddp) { 672 rele2 = cwdi->cwdi_rdir; 673 vref(newdp); 674 cwdi->cwdi_rdir = newdp; 675 } 676 rw_exit(&cwdi->cwdi_lock); 677 cwdfree(cwdi); 678 if (rele1 != NULL) 679 vrele(rele1); 680 if (rele2 != NULL) 681 vrele(rele2); 682 mutex_enter(proc_lock); 683 break; 684 } 685 mutex_exit(proc_lock); 686 } while (retry); 687 688 if (rootvnode == olddp) { 689 vrele(rootvnode); 690 vref(newdp); 691 rootvnode = newdp; 692 } 693 vput(newdp); 694 } 695 696 /* 697 * Start extended attributes 698 */ 699 static int 700 start_extattr(struct mount *mp) 701 { 702 int error; 703 704 error = VFS_EXTATTRCTL(mp, EXTATTR_CMD_START, NULL, 0, NULL); 705 if (error) 706 printf("%s: failed to start extattr: error = %d\n", 707 mp->mnt_stat.f_mntonname, error); 708 709 return error; 710 } 711 712 int 713 mount_domount(struct lwp *l, vnode_t **vpp, struct vfsops *vfsops, 714 const char *path, int flags, void *data, size_t *data_len) 715 { 716 vnode_t *vp = *vpp; 717 struct mount *mp; 718 struct pathbuf *pb; 719 struct nameidata nd; 720 int error; 721 722 error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT, 723 KAUTH_REQ_SYSTEM_MOUNT_NEW, vp, KAUTH_ARG(flags), data); 724 if (error) { 725 vfs_delref(vfsops); 726 return error; 727 } 728 729 /* Cannot make a non-dir a mount-point (from here anyway). */ 730 if (vp->v_type != VDIR) { 731 vfs_delref(vfsops); 732 return ENOTDIR; 733 } 734 735 if (flags & MNT_EXPORTED) { 736 vfs_delref(vfsops); 737 return EINVAL; 738 } 739 740 if ((mp = vfs_mountalloc(vfsops, vp)) == NULL) { 741 vfs_delref(vfsops); 742 return ENOMEM; 743 } 744 745 mp->mnt_stat.f_owner = kauth_cred_geteuid(l->l_cred); 746 747 /* 748 * The underlying file system may refuse the mount for 749 * various reasons. Allow the user to force it to happen. 750 * 751 * Set the mount level flags. 752 */ 753 mp->mnt_flag = flags & (MNT_BASIC_FLAGS | MNT_FORCE | MNT_IGNORE); 754 755 mutex_enter(&mp->mnt_updating); 756 error = VFS_MOUNT(mp, path, data, data_len); 757 mp->mnt_flag &= ~MNT_OP_FLAGS; 758 759 if (error != 0) 760 goto err_unmounted; 761 762 /* 763 * Validate and prepare the mount point. 764 */ 765 error = pathbuf_copyin(path, &pb); 766 if (error != 0) { 767 goto err_mounted; 768 } 769 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb); 770 error = namei(&nd); 771 pathbuf_destroy(pb); 772 if (error != 0) { 773 goto err_mounted; 774 } 775 if (nd.ni_vp != vp) { 776 vput(nd.ni_vp); 777 error = EINVAL; 778 goto err_mounted; 779 } 780 if (vp->v_mountedhere != NULL) { 781 vput(nd.ni_vp); 782 error = EBUSY; 783 goto err_mounted; 784 } 785 error = vinvalbuf(vp, V_SAVE, l->l_cred, l, 0, 0); 786 if (error != 0) { 787 vput(nd.ni_vp); 788 goto err_mounted; 789 } 790 791 /* 792 * Put the new filesystem on the mount list after root. 793 */ 794 cache_purge(vp); 795 mp->mnt_iflag &= ~IMNT_WANTRDWR; 796 797 mountlist_append(mp); 798 if ((mp->mnt_flag & (MNT_RDONLY | MNT_ASYNC)) == 0) 799 vfs_syncer_add_to_worklist(mp); 800 vp->v_mountedhere = mp; 801 vput(nd.ni_vp); 802 803 mount_checkdirs(vp); 804 mutex_exit(&mp->mnt_updating); 805 806 /* Hold an additional reference to the mount across VFS_START(). */ 807 vfs_ref(mp); 808 (void) VFS_STATVFS(mp, &mp->mnt_stat); 809 error = VFS_START(mp, 0); 810 if (error) { 811 vrele(vp); 812 } else if (flags & MNT_EXTATTR) { 813 (void)start_extattr(mp); 814 } 815 /* Drop reference held for VFS_START(). */ 816 vfs_rele(mp); 817 *vpp = NULL; 818 return error; 819 820 err_mounted: 821 if (VFS_UNMOUNT(mp, MNT_FORCE) != 0) 822 panic("Unmounting fresh file system failed"); 823 824 err_unmounted: 825 vp->v_mountedhere = NULL; 826 mutex_exit(&mp->mnt_updating); 827 vfs_rele(mp); 828 829 return error; 830 } 831 832 /* 833 * Do the actual file system unmount. File system is assumed to have 834 * been locked by the caller. 835 * 836 * => Caller hold reference to the mount, explicitly for dounmount(). 837 */ 838 int 839 dounmount(struct mount *mp, int flags, struct lwp *l) 840 { 841 vnode_t *coveredvp; 842 int error, async, used_syncer, used_extattr; 843 const bool was_suspended = fstrans_is_owner(mp); 844 845 #if NVERIEXEC > 0 846 error = veriexec_unmountchk(mp); 847 if (error) 848 return (error); 849 #endif /* NVERIEXEC > 0 */ 850 851 if (!was_suspended) { 852 error = vfs_suspend(mp, 0); 853 if (error) { 854 return error; 855 } 856 } 857 858 KASSERT((mp->mnt_iflag & IMNT_GONE) == 0); 859 860 used_syncer = (mp->mnt_iflag & IMNT_ONWORKLIST) != 0; 861 used_extattr = mp->mnt_flag & MNT_EXTATTR; 862 863 mp->mnt_iflag |= IMNT_UNMOUNT; 864 mutex_enter(&mp->mnt_updating); 865 async = mp->mnt_flag & MNT_ASYNC; 866 mp->mnt_flag &= ~MNT_ASYNC; 867 cache_purgevfs(mp); /* remove cache entries for this file sys */ 868 if (used_syncer) 869 vfs_syncer_remove_from_worklist(mp); 870 error = 0; 871 if (((mp->mnt_flag & MNT_RDONLY) == 0) && ((flags & MNT_FORCE) == 0)) { 872 error = VFS_SYNC(mp, MNT_WAIT, l->l_cred); 873 } 874 if (error == 0 || (flags & MNT_FORCE)) { 875 error = VFS_UNMOUNT(mp, flags); 876 } 877 if (error) { 878 mp->mnt_iflag &= ~IMNT_UNMOUNT; 879 if ((mp->mnt_flag & (MNT_RDONLY | MNT_ASYNC)) == 0) 880 vfs_syncer_add_to_worklist(mp); 881 mp->mnt_flag |= async; 882 mutex_exit(&mp->mnt_updating); 883 if (!was_suspended) 884 vfs_resume(mp); 885 if (used_extattr) { 886 if (start_extattr(mp) != 0) 887 mp->mnt_flag &= ~MNT_EXTATTR; 888 else 889 mp->mnt_flag |= MNT_EXTATTR; 890 } 891 return (error); 892 } 893 mutex_exit(&mp->mnt_updating); 894 895 /* 896 * mark filesystem as gone to prevent further umounts 897 * after mnt_umounting lock is gone, this also prevents 898 * vfs_busy() from succeeding. 899 */ 900 mp->mnt_iflag |= IMNT_GONE; 901 if (!was_suspended) 902 vfs_resume(mp); 903 904 if ((coveredvp = mp->mnt_vnodecovered) != NULLVP) { 905 vn_lock(coveredvp, LK_EXCLUSIVE | LK_RETRY); 906 coveredvp->v_mountedhere = NULL; 907 VOP_UNLOCK(coveredvp); 908 } 909 mountlist_remove(mp); 910 if (TAILQ_FIRST(&mp->mnt_vnodelist) != NULL) 911 panic("unmount: dangling vnode"); 912 vfs_hooks_unmount(mp); 913 914 vfs_rele(mp); /* reference from mount() */ 915 if (coveredvp != NULLVP) { 916 vrele(coveredvp); 917 } 918 return (0); 919 } 920 921 /* 922 * Unmount all file systems. 923 * We traverse the list in reverse order under the assumption that doing so 924 * will avoid needing to worry about dependencies. 925 */ 926 bool 927 vfs_unmountall(struct lwp *l) 928 { 929 930 printf("unmounting file systems...\n"); 931 return vfs_unmountall1(l, true, true); 932 } 933 934 static void 935 vfs_unmount_print(struct mount *mp, const char *pfx) 936 { 937 938 aprint_verbose("%sunmounted %s on %s type %s\n", pfx, 939 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname, 940 mp->mnt_stat.f_fstypename); 941 } 942 943 /* 944 * Return the mount with the highest generation less than "gen". 945 */ 946 static struct mount * 947 vfs_unmount_next(uint64_t gen) 948 { 949 mount_iterator_t *iter; 950 struct mount *mp, *nmp; 951 952 nmp = NULL; 953 954 mountlist_iterator_init(&iter); 955 while ((mp = mountlist_iterator_next(iter)) != NULL) { 956 if ((nmp == NULL || mp->mnt_gen > nmp->mnt_gen) && 957 mp->mnt_gen < gen) { 958 if (nmp != NULL) 959 vfs_rele(nmp); 960 nmp = mp; 961 vfs_ref(nmp); 962 } 963 } 964 mountlist_iterator_destroy(iter); 965 966 return nmp; 967 } 968 969 bool 970 vfs_unmount_forceone(struct lwp *l) 971 { 972 struct mount *mp; 973 int error; 974 975 mp = vfs_unmount_next(mountgen); 976 if (mp == NULL) { 977 return false; 978 } 979 980 #ifdef DEBUG 981 printf("forcefully unmounting %s (%s)...\n", 982 mp->mnt_stat.f_mntonname, mp->mnt_stat.f_mntfromname); 983 #endif 984 if ((error = dounmount(mp, MNT_FORCE, l)) == 0) { 985 vfs_unmount_print(mp, "forcefully "); 986 return true; 987 } else { 988 vfs_rele(mp); 989 } 990 991 #ifdef DEBUG 992 printf("forceful unmount of %s failed with error %d\n", 993 mp->mnt_stat.f_mntonname, error); 994 #endif 995 996 return false; 997 } 998 999 bool 1000 vfs_unmountall1(struct lwp *l, bool force, bool verbose) 1001 { 1002 struct mount *mp; 1003 bool any_error = false, progress = false; 1004 uint64_t gen; 1005 int error; 1006 1007 gen = mountgen; 1008 for (;;) { 1009 mp = vfs_unmount_next(gen); 1010 if (mp == NULL) 1011 break; 1012 gen = mp->mnt_gen; 1013 1014 #ifdef DEBUG 1015 printf("unmounting %p %s (%s)...\n", 1016 (void *)mp, mp->mnt_stat.f_mntonname, 1017 mp->mnt_stat.f_mntfromname); 1018 #endif 1019 if ((error = dounmount(mp, force ? MNT_FORCE : 0, l)) == 0) { 1020 vfs_unmount_print(mp, ""); 1021 progress = true; 1022 } else { 1023 vfs_rele(mp); 1024 if (verbose) { 1025 printf("unmount of %s failed with error %d\n", 1026 mp->mnt_stat.f_mntonname, error); 1027 } 1028 any_error = true; 1029 } 1030 } 1031 if (verbose) { 1032 printf("unmounting done\n"); 1033 } 1034 if (any_error && verbose) { 1035 printf("WARNING: some file systems would not unmount\n"); 1036 } 1037 return progress; 1038 } 1039 1040 void 1041 vfs_sync_all(struct lwp *l) 1042 { 1043 printf("syncing disks... "); 1044 1045 /* remove user processes from run queue */ 1046 suspendsched(); 1047 (void)spl0(); 1048 1049 /* avoid coming back this way again if we panic. */ 1050 doing_shutdown = 1; 1051 1052 do_sys_sync(l); 1053 1054 /* Wait for sync to finish. */ 1055 if (buf_syncwait() != 0) { 1056 #if defined(DDB) && defined(DEBUG_HALT_BUSY) 1057 Debugger(); 1058 #endif 1059 printf("giving up\n"); 1060 return; 1061 } else 1062 printf("done\n"); 1063 } 1064 1065 /* 1066 * Sync and unmount file systems before shutting down. 1067 */ 1068 void 1069 vfs_shutdown(void) 1070 { 1071 lwp_t *l = curlwp; 1072 1073 vfs_sync_all(l); 1074 1075 /* 1076 * If we have paniced - do not make the situation potentially 1077 * worse by unmounting the file systems. 1078 */ 1079 if (panicstr != NULL) { 1080 return; 1081 } 1082 1083 /* Unmount file systems. */ 1084 vfs_unmountall(l); 1085 } 1086 1087 /* 1088 * Print a list of supported file system types (used by vfs_mountroot) 1089 */ 1090 static void 1091 vfs_print_fstypes(void) 1092 { 1093 struct vfsops *v; 1094 int cnt = 0; 1095 1096 mutex_enter(&vfs_list_lock); 1097 LIST_FOREACH(v, &vfs_list, vfs_list) 1098 ++cnt; 1099 mutex_exit(&vfs_list_lock); 1100 1101 if (cnt == 0) { 1102 printf("WARNING: No file system modules have been loaded.\n"); 1103 return; 1104 } 1105 1106 printf("Supported file systems:"); 1107 mutex_enter(&vfs_list_lock); 1108 LIST_FOREACH(v, &vfs_list, vfs_list) { 1109 printf(" %s", v->vfs_name); 1110 } 1111 mutex_exit(&vfs_list_lock); 1112 printf("\n"); 1113 } 1114 1115 /* 1116 * Mount the root file system. If the operator didn't specify a 1117 * file system to use, try all possible file systems until one 1118 * succeeds. 1119 */ 1120 int 1121 vfs_mountroot(void) 1122 { 1123 struct vfsops *v; 1124 int error = ENODEV; 1125 1126 if (root_device == NULL) 1127 panic("vfs_mountroot: root device unknown"); 1128 1129 switch (device_class(root_device)) { 1130 case DV_IFNET: 1131 if (rootdev != NODEV) 1132 panic("vfs_mountroot: rootdev set for DV_IFNET " 1133 "(0x%llx -> %llu,%llu)", 1134 (unsigned long long)rootdev, 1135 (unsigned long long)major(rootdev), 1136 (unsigned long long)minor(rootdev)); 1137 break; 1138 1139 case DV_DISK: 1140 if (rootdev == NODEV) 1141 panic("vfs_mountroot: rootdev not set for DV_DISK"); 1142 if (bdevvp(rootdev, &rootvp)) 1143 panic("vfs_mountroot: can't get vnode for rootdev"); 1144 error = VOP_OPEN(rootvp, FREAD, FSCRED); 1145 if (error) { 1146 printf("vfs_mountroot: can't open root device\n"); 1147 return (error); 1148 } 1149 break; 1150 1151 case DV_VIRTUAL: 1152 break; 1153 1154 default: 1155 printf("%s: inappropriate for root file system\n", 1156 device_xname(root_device)); 1157 return (ENODEV); 1158 } 1159 1160 /* 1161 * If user specified a root fs type, use it. Make sure the 1162 * specified type exists and has a mount_root() 1163 */ 1164 if (strcmp(rootfstype, ROOT_FSTYPE_ANY) != 0) { 1165 v = vfs_getopsbyname(rootfstype); 1166 error = EFTYPE; 1167 if (v != NULL) { 1168 if (v->vfs_mountroot != NULL) { 1169 error = (v->vfs_mountroot)(); 1170 } 1171 v->vfs_refcount--; 1172 } 1173 goto done; 1174 } 1175 1176 /* 1177 * Try each file system currently configured into the kernel. 1178 */ 1179 mutex_enter(&vfs_list_lock); 1180 LIST_FOREACH(v, &vfs_list, vfs_list) { 1181 if (v->vfs_mountroot == NULL) 1182 continue; 1183 #ifdef DEBUG 1184 aprint_normal("mountroot: trying %s...\n", v->vfs_name); 1185 #endif 1186 v->vfs_refcount++; 1187 mutex_exit(&vfs_list_lock); 1188 error = (*v->vfs_mountroot)(); 1189 mutex_enter(&vfs_list_lock); 1190 v->vfs_refcount--; 1191 if (!error) { 1192 aprint_normal("root file system type: %s\n", 1193 v->vfs_name); 1194 break; 1195 } 1196 } 1197 mutex_exit(&vfs_list_lock); 1198 1199 if (v == NULL) { 1200 vfs_print_fstypes(); 1201 printf("no file system for %s", device_xname(root_device)); 1202 if (device_class(root_device) == DV_DISK) 1203 printf(" (dev 0x%llx)", (unsigned long long)rootdev); 1204 printf("\n"); 1205 error = EFTYPE; 1206 } 1207 1208 done: 1209 if (error && device_class(root_device) == DV_DISK) { 1210 VOP_CLOSE(rootvp, FREAD, FSCRED); 1211 vrele(rootvp); 1212 } 1213 if (error == 0) { 1214 mount_iterator_t *iter; 1215 struct mount *mp; 1216 extern struct cwdinfo cwdi0; 1217 1218 mountlist_iterator_init(&iter); 1219 mp = mountlist_iterator_next(iter); 1220 KASSERT(mp != NULL); 1221 mountlist_iterator_destroy(iter); 1222 1223 mp->mnt_flag |= MNT_ROOTFS; 1224 mp->mnt_op->vfs_refcount++; 1225 1226 /* 1227 * Get the vnode for '/'. Set cwdi0.cwdi_cdir to 1228 * reference it. 1229 */ 1230 error = VFS_ROOT(mp, &rootvnode); 1231 if (error) 1232 panic("cannot find root vnode, error=%d", error); 1233 cwdi0.cwdi_cdir = rootvnode; 1234 vref(cwdi0.cwdi_cdir); 1235 VOP_UNLOCK(rootvnode); 1236 cwdi0.cwdi_rdir = NULL; 1237 1238 /* 1239 * Now that root is mounted, we can fixup initproc's CWD 1240 * info. All other processes are kthreads, which merely 1241 * share proc0's CWD info. 1242 */ 1243 initproc->p_cwdi->cwdi_cdir = rootvnode; 1244 vref(initproc->p_cwdi->cwdi_cdir); 1245 initproc->p_cwdi->cwdi_rdir = NULL; 1246 /* 1247 * Enable loading of modules from the filesystem 1248 */ 1249 module_load_vfs_init(); 1250 1251 } 1252 return (error); 1253 } 1254 1255 /* 1256 * mount_specific_key_create -- 1257 * Create a key for subsystem mount-specific data. 1258 */ 1259 int 1260 mount_specific_key_create(specificdata_key_t *keyp, specificdata_dtor_t dtor) 1261 { 1262 1263 return specificdata_key_create(mount_specificdata_domain, keyp, dtor); 1264 } 1265 1266 /* 1267 * mount_specific_key_delete -- 1268 * Delete a key for subsystem mount-specific data. 1269 */ 1270 void 1271 mount_specific_key_delete(specificdata_key_t key) 1272 { 1273 1274 specificdata_key_delete(mount_specificdata_domain, key); 1275 } 1276 1277 /* 1278 * mount_initspecific -- 1279 * Initialize a mount's specificdata container. 1280 */ 1281 void 1282 mount_initspecific(struct mount *mp) 1283 { 1284 int error __diagused; 1285 1286 error = specificdata_init(mount_specificdata_domain, 1287 &mp->mnt_specdataref); 1288 KASSERT(error == 0); 1289 } 1290 1291 /* 1292 * mount_finispecific -- 1293 * Finalize a mount's specificdata container. 1294 */ 1295 void 1296 mount_finispecific(struct mount *mp) 1297 { 1298 1299 specificdata_fini(mount_specificdata_domain, &mp->mnt_specdataref); 1300 } 1301 1302 /* 1303 * mount_getspecific -- 1304 * Return mount-specific data corresponding to the specified key. 1305 */ 1306 void * 1307 mount_getspecific(struct mount *mp, specificdata_key_t key) 1308 { 1309 1310 return specificdata_getspecific(mount_specificdata_domain, 1311 &mp->mnt_specdataref, key); 1312 } 1313 1314 /* 1315 * mount_setspecific -- 1316 * Set mount-specific data corresponding to the specified key. 1317 */ 1318 void 1319 mount_setspecific(struct mount *mp, specificdata_key_t key, void *data) 1320 { 1321 1322 specificdata_setspecific(mount_specificdata_domain, 1323 &mp->mnt_specdataref, key, data); 1324 } 1325 1326 /* 1327 * Check to see if a filesystem is mounted on a block device. 1328 */ 1329 int 1330 vfs_mountedon(vnode_t *vp) 1331 { 1332 vnode_t *vq; 1333 int error = 0; 1334 1335 if (vp->v_type != VBLK) 1336 return ENOTBLK; 1337 if (spec_node_getmountedfs(vp) != NULL) 1338 return EBUSY; 1339 if (spec_node_lookup_by_dev(vp->v_type, vp->v_rdev, &vq) == 0) { 1340 if (spec_node_getmountedfs(vq) != NULL) 1341 error = EBUSY; 1342 vrele(vq); 1343 } 1344 1345 return error; 1346 } 1347 1348 /* 1349 * Check if a device pointed to by vp is mounted. 1350 * 1351 * Returns: 1352 * EINVAL if it's not a disk 1353 * EBUSY if it's a disk and mounted 1354 * 0 if it's a disk and not mounted 1355 */ 1356 int 1357 rawdev_mounted(vnode_t *vp, vnode_t **bvpp) 1358 { 1359 vnode_t *bvp; 1360 dev_t dev; 1361 int d_type; 1362 1363 bvp = NULL; 1364 d_type = D_OTHER; 1365 1366 if (iskmemvp(vp)) 1367 return EINVAL; 1368 1369 switch (vp->v_type) { 1370 case VCHR: { 1371 const struct cdevsw *cdev; 1372 1373 dev = vp->v_rdev; 1374 cdev = cdevsw_lookup(dev); 1375 if (cdev != NULL) { 1376 dev_t blkdev; 1377 1378 blkdev = devsw_chr2blk(dev); 1379 if (blkdev != NODEV) { 1380 if (vfinddev(blkdev, VBLK, &bvp) != 0) { 1381 d_type = (cdev->d_flag & D_TYPEMASK); 1382 /* XXX: what if bvp disappears? */ 1383 vrele(bvp); 1384 } 1385 } 1386 } 1387 1388 break; 1389 } 1390 1391 case VBLK: { 1392 const struct bdevsw *bdev; 1393 1394 dev = vp->v_rdev; 1395 bdev = bdevsw_lookup(dev); 1396 if (bdev != NULL) 1397 d_type = (bdev->d_flag & D_TYPEMASK); 1398 1399 bvp = vp; 1400 1401 break; 1402 } 1403 1404 default: 1405 break; 1406 } 1407 1408 if (d_type != D_DISK) 1409 return EINVAL; 1410 1411 if (bvpp != NULL) 1412 *bvpp = bvp; 1413 1414 /* 1415 * XXX: This is bogus. We should be failing the request 1416 * XXX: not only if this specific slice is mounted, but 1417 * XXX: if it's on a disk with any other mounted slice. 1418 */ 1419 if (vfs_mountedon(bvp)) 1420 return EBUSY; 1421 1422 return 0; 1423 } 1424 1425 /* 1426 * Make a 'unique' number from a mount type name. 1427 */ 1428 long 1429 makefstype(const char *type) 1430 { 1431 long rv; 1432 1433 for (rv = 0; *type; type++) { 1434 rv <<= 2; 1435 rv ^= *type; 1436 } 1437 return rv; 1438 } 1439 1440 static struct mountlist_entry * 1441 mountlist_alloc(enum mountlist_type type, struct mount *mp) 1442 { 1443 struct mountlist_entry *me; 1444 1445 me = kmem_zalloc(sizeof(*me), KM_SLEEP); 1446 me->me_mount = mp; 1447 me->me_type = type; 1448 1449 return me; 1450 } 1451 1452 static void 1453 mountlist_free(struct mountlist_entry *me) 1454 { 1455 1456 kmem_free(me, sizeof(*me)); 1457 } 1458 1459 void 1460 mountlist_iterator_init(mount_iterator_t **mip) 1461 { 1462 struct mountlist_entry *me; 1463 1464 me = mountlist_alloc(ME_MARKER, NULL); 1465 mutex_enter(&mountlist_lock); 1466 TAILQ_INSERT_HEAD(&mountlist, me, me_list); 1467 mutex_exit(&mountlist_lock); 1468 *mip = (mount_iterator_t *)me; 1469 } 1470 1471 void 1472 mountlist_iterator_destroy(mount_iterator_t *mi) 1473 { 1474 struct mountlist_entry *marker = &mi->mi_entry; 1475 1476 if (marker->me_mount != NULL) 1477 vfs_unbusy(marker->me_mount); 1478 1479 mutex_enter(&mountlist_lock); 1480 TAILQ_REMOVE(&mountlist, marker, me_list); 1481 mutex_exit(&mountlist_lock); 1482 1483 mountlist_free(marker); 1484 1485 } 1486 1487 /* 1488 * Return the next mount or NULL for this iterator. 1489 * Mark it busy on success. 1490 */ 1491 static inline struct mount * 1492 _mountlist_iterator_next(mount_iterator_t *mi, bool wait) 1493 { 1494 struct mountlist_entry *me, *marker = &mi->mi_entry; 1495 struct mount *mp; 1496 int error; 1497 1498 if (marker->me_mount != NULL) { 1499 vfs_unbusy(marker->me_mount); 1500 marker->me_mount = NULL; 1501 } 1502 1503 mutex_enter(&mountlist_lock); 1504 for (;;) { 1505 KASSERT(marker->me_type == ME_MARKER); 1506 1507 me = TAILQ_NEXT(marker, me_list); 1508 if (me == NULL) { 1509 /* End of list: keep marker and return. */ 1510 mutex_exit(&mountlist_lock); 1511 return NULL; 1512 } 1513 TAILQ_REMOVE(&mountlist, marker, me_list); 1514 TAILQ_INSERT_AFTER(&mountlist, me, marker, me_list); 1515 1516 /* Skip other markers. */ 1517 if (me->me_type != ME_MOUNT) 1518 continue; 1519 1520 /* Take an initial reference for vfs_busy() below. */ 1521 mp = me->me_mount; 1522 KASSERT(mp != NULL); 1523 vfs_ref(mp); 1524 mutex_exit(&mountlist_lock); 1525 1526 /* Try to mark this mount busy and return on success. */ 1527 if (wait) 1528 error = vfs_busy(mp); 1529 else 1530 error = vfs_trybusy(mp); 1531 if (error == 0) { 1532 vfs_rele(mp); 1533 marker->me_mount = mp; 1534 return mp; 1535 } 1536 vfs_rele(mp); 1537 mutex_enter(&mountlist_lock); 1538 } 1539 } 1540 1541 struct mount * 1542 mountlist_iterator_next(mount_iterator_t *mi) 1543 { 1544 1545 return _mountlist_iterator_next(mi, true); 1546 } 1547 1548 struct mount * 1549 mountlist_iterator_trynext(mount_iterator_t *mi) 1550 { 1551 1552 return _mountlist_iterator_next(mi, false); 1553 } 1554 1555 /* 1556 * Attach new mount to the end of the mount list. 1557 */ 1558 void 1559 mountlist_append(struct mount *mp) 1560 { 1561 struct mountlist_entry *me; 1562 1563 me = mountlist_alloc(ME_MOUNT, mp); 1564 mutex_enter(&mountlist_lock); 1565 TAILQ_INSERT_TAIL(&mountlist, me, me_list); 1566 mutex_exit(&mountlist_lock); 1567 } 1568 1569 /* 1570 * Remove mount from mount list. 1571 */void 1572 mountlist_remove(struct mount *mp) 1573 { 1574 struct mountlist_entry *me; 1575 1576 mutex_enter(&mountlist_lock); 1577 TAILQ_FOREACH(me, &mountlist, me_list) 1578 if (me->me_type == ME_MOUNT && me->me_mount == mp) 1579 break; 1580 KASSERT(me != NULL); 1581 TAILQ_REMOVE(&mountlist, me, me_list); 1582 mutex_exit(&mountlist_lock); 1583 mountlist_free(me); 1584 } 1585 1586 /* 1587 * Unlocked variant to traverse the mountlist. 1588 * To be used from DDB only. 1589 */ 1590 struct mount * 1591 _mountlist_next(struct mount *mp) 1592 { 1593 struct mountlist_entry *me; 1594 1595 if (mp == NULL) { 1596 me = TAILQ_FIRST(&mountlist); 1597 } else { 1598 TAILQ_FOREACH(me, &mountlist, me_list) 1599 if (me->me_type == ME_MOUNT && me->me_mount == mp) 1600 break; 1601 if (me != NULL) 1602 me = TAILQ_NEXT(me, me_list); 1603 } 1604 1605 while (me != NULL && me->me_type != ME_MOUNT) 1606 me = TAILQ_NEXT(me, me_list); 1607 1608 return (me ? me->me_mount : NULL); 1609 } 1610